Calculation and experimental analysis of the muon cross sections
Astrophysics and Astronomy
Final Report Abstract
Precise simulations of high-energy muons are important for many applications in astroparticle physics, for example for neutrino observatories or cosmic ray experiments. The aim of this project was to improve the accuracy of muon energy loss cross sections using theoretical and experimental methods. We performed analytical calculations for electron-positron pair production as well as bremsstrahlung cross sections, using more precise screening functions as well as a more accurate treatment of radiative corrections. Compared to standard cross sections which were previously used, our calculations show a decrease of 0.5% for the pair production cross sections as well as a 2% increase of the bremsstrahlung cross section. Since the neutrino energy spectra in astroparticle physics are indirectly reconstructed using these cross sections, the corrections are also relevant for the reconstruction of atmospheric and astrophysical neutrino fluxes. The link between theoretical calculations and simulations is provided by PROPOSAL, a Monte Carlo simulation tool developed in Dortmund. Significant improvements in efficiency, maintainability and usability for PROPOSAL have been made. Among other experiments, PROPOSAL is used by the IceCube neutrino observatory and now also in the air shower simulation framework CORSIKA 8, which can therefore directly benefit from the results of this project. To measure the muon energy loss cross sections experimentally, a general method based on observables correlated to the energy losses of single muons inside the IceCube detector was developed. However, simulation studies revealed that the existing IceCube parameter estimation algorithms for the observables were not accurate enough for the intended purpose. Therefore, first a novel approach for this parameter estimation in IceCube, combining the advantages of convolutional neural networks and classical reconstruction approaches, was invented and realised. This approach provides the required improvement of the reconstruction resolution, together with a significant boost in efficiency. In addition, the developed methods are general enough to be used for other scientific tasks beyond the scope of this project, for example for on-line reconstruction tasks conducted directly at the South Pole, where resources are limited.
Publications
- “Deep Learning in Physics exemplified by the Reconstruction of Muon-Neutrino Events in IceCube”. In: 35th International Cosmic Ray Conference (ICRC 2017). Vol. 301. Proceedings of Science. 2017, p. 1057
M. Huennefeld, for the IceCube collaboration
(See online at https://doi.org/10.22323/1.301.1057) - Coulomb corrections to the bremsstrahlung and electron pair production cross section of high-energy muons on extended nuclei. 2018
Alexander Sandrock and Wolfgang Rhode
(See online at https://doi.org/10.48550/arXiv.1807.08475) - “Recent improvements for the lepton propagator PRO- POSAL”. in: Computer Physics Communications 242 (2019), pp. 132–144
Mario Dunsch et al.
(See online at https://doi.org/10.1016/j.cpc.2019.03.021) - “Reconstruction Techniques in IceCube using Convolutional and Generative Neural Networks”. In: VLVνT 2019. Vol. 207. EPJ Web of Conferences. 2019, p. 05005
M. Huennefeld, for the IceCube collaboration
(See online at https://doi.org/10.1051/epjconf/201920705005) - “The effect of improved highenergy muon cross-sections”. In: 36th International Cosmic Rays Conference (ICRC2019). Vol. 358. Proceedings of Science. 2019, p. 429
J. Soedingrekso, A. Sandrock, and W. Rhode
(See online at https://doi.org/10.22323/1.358.0429) - “Feasibility study to measure the muon bremsstrahlung cross section with the energy loss profile using neutrino telescopes”. In: Journal of Physics: Conference Series 1690 (2020), p. 012020
J. Soedingrekso et al.
(See online at https://doi.org/10.1088/1742-6596/1690/1/012020) - “PROPOSAL: A library to propagate leptons and high energy photons”. In: Journal of Physics: Conference Series 1690 (2020), p. 012021
J.-M. Alameddine et al.
(See online at https://doi.org/10.1088/1742-6596/1690/1/012021)
